The present invention relates to a diode of plane structure with variable capacity and abrupt profile, in which the law of variation of the capacity as a function of the control voltage may be any whatsoever, since it is a consequence of the plane structure of the diode and of the profile of the doping level of the semiconductor material surface layer, this profile being obtained by an ion implantation method.
The diode of the invention may be formed not only on silicon but also on materials of the group III-IV such as GaAs. Similarly, it may be in the form of a discrete component encapsulated in a case or mounted plane with beam lead connections or an integrated component in a low frequency or ultra high frequency integrated circuit.
Known variable capacity diodes are formed by ion implantation or by epitaxy of successive layers; they have a vertical structure. But it is not possible to obtain a hyperabrupt profile by implantation in a vertical structure, because of the variations in the doping obtained by implantation. It is only possible by epitaxy, but epitaxy is not applicable in this case to integrated circuits: it is not possible to epitaxy on a semiconductor material wafer only (at the position of the variable capacity diodes and not elsewhere) at the position of the variable capacity diodes, and not elsewhere. Or else that requires a complicated and delicate technology.